Secretary of State Hillary Clinton, seen Jan. 18 in Washington, D.C., formally resigned from the office Friday. Clinton was succeeded by John F. Kerry, a former Democratic senator from Massachusetts.

Written by

BRADLEY KLAPPER
and MATTHEW LEE

WASHINGTON - Hillary R. Clinton formally resigned Friday as America's 67th secretary of state, capping a four-year tenure in the office that saw her set a record for the number of countries visited.

In a letter sent to President Barack Obama shortly before she was to leave the State Department for the last time in her official capacity, Clinton thanked her former foe for the 2008 Democratic presidential nomination for the opportunity to serve in his administration.

"I am more convinced than ever in the strength and staying power of America's global leadership and our capacity to be a force for ...